Pithouses (sqémél
) were used by the Stó:lō in the upper Fraser Valley region, as well as around the Harrison Lake area. The building of pithouses was a communal effort, often involving 20 to 30 family members and neighbours. Digging sticks were used to loosen the soil to dig out the circle, and large flat pieces of wood were used to scoop the dirt into baskets. This fill was deposited near the site, to be used later to cover the roof.

Green timber was measured using bark rope. It was then cut and the bark removed. Left in the round, the timber was then hauled to the site. The upright posts were sunk about half a metre into the ground near the centre of the freshly dug circle, after which the earth all around the floor of the house was stamped flat using feet and flat sticks. Four rafters were placed about two-thirds of a metre into the ground at an angle representing the slope of the roof, and supported by notches in the upright posts.

Flexible willow twigs were used to bind the posts and rafters. The rafters did not meet in the centre, in order to allow for a top entrance opening. Four horizontal timbers that were lashed and notched to the rafter ends supported this opening. Two side rafters were lashed to each main rafter for support. Horizontal poles were lashed between the rafters to support the roof coverings of vertical poles, bark and soil.

A notched ladder was placed in the hole at the top of the building. The ladder had one step missing, which the family members were aware of, to help protect the inhabitants from unwanted invaders. A second entrance was built into the side of the house for the elders and children.

Pithouses ranged in size and could house up to 20 people (less occupants than in the longhouses). Most pithouses were round, but some were also square or rectangular. Like in the longhouses, sleeping areas and storage spaces were around the edges of the structure near the walls, and the central area was a communal space for cooking, eating and other household activities.